Ignition timing problems

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fatblokeabroad
Posts: 26
Joined: 11 Apr 2021 14:39
Location: Puglia, Italy

Ignition timing problems

Post by fatblokeabroad »

Good afternoon,
I have been fettling my 350 Strada prior to registering it in Italy and decided to check the ignition timing as I had a slight misfire on rising revs. I checked the valve clearances and all was correct on PMS 1 and 2. I followed the instructions in the NLM blue book and used a strobe gun I bought a while ago. I was more than a little surprised to find that, at high revs (my tacho is knackered, but thats another story), the strobe was indicating alignment of PMS 2 with the crank axis mark, not ANT 1 as expected. I tried moving the magnetic pick-up plate to change the alignment but it did not seem to make a difference.
can someone advise me as to what I have done wrong, is it possible to have the timing so far out and still have a running engine?
MickeyMoto
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Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Ignition timing problems

Post by MickeyMoto »

Older, non electric start bikes have the timing mark at 9 O'clock, not 12 O'Clock. Is yours an older bike? If so, you may find you are looking at the wrong place. If not, gawd knows! :)
fatblokeabroad
Posts: 26
Joined: 11 Apr 2021 14:39
Location: Puglia, Italy

Re: Ignition timing problems

Post by fatblokeabroad »

Thanks,
Yes I did a double check, its a 76 Strada and everything is done from the 9 o clock position. I'm glad I'm not the only baffled person on the forum.
Steve Brown
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Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: Ignition timing problems

Post by Steve Brown »

Is the strobe one of those with an adjustable advance setting or a fixed one? You have actually connected the strobe to the front cylinder lead too?
Sorry but I feel the need to ask!
All donations to the rest home for old Camels, Leicestershire.
fatblokeabroad
Posts: 26
Joined: 11 Apr 2021 14:39
Location: Puglia, Italy

Re: Ignition timing problems

Post by fatblokeabroad »

It's a fixed strobe and yes I am connected to the front cylinder HT lead and the clamp probe is in the right direction.
fatblokeabroad
Posts: 26
Joined: 11 Apr 2021 14:39
Location: Puglia, Italy

Re: Ignition timing problems

Post by fatblokeabroad »

Further to my last, the gun is strobing as expected only it is strobing on PMS 2 not ANT 1 as expected.
Steve Brown
Posts: 1390
Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: Ignition timing problems

Post by Steve Brown »

Later flywheel fitted? How does it look if you aim the syrobe athe centre of the camsahft i.e. vertically from flywheel centre?
All donations to the rest home for old Camels, Leicestershire.
fatblokeabroad
Posts: 26
Joined: 11 Apr 2021 14:39
Location: Puglia, Italy

Re: Ignition timing problems

Post by fatblokeabroad »

Just tried again and no, there are no alignments at the 12 o clock position.
If I strobe the 9 o clock position (normal position for a 76 Strada) I can see the ANT1 mark illuminated but it is about 30 degrees behind the case marking, so about 8 o clock. I do not seem to have enough play on the ignition pick-up housing. Any thoughts
MickeyMoto
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Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Ignition timing problems

Post by MickeyMoto »

So it is 30 degrees advanced. Just to clarify, you need to move the trigger anti clockwise to retard. In which direction do you have movement on the trigger?

PS this may be a complete load of bollocks and it is the other way around!

Have you tried the static timing point on the trigger? The arrow lining up with the marker.
mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Ignition timing problems

Post by mbmm350s »

Hi I think you should remove the rotor and confirm the cam timing marks are correctly aligned as per fig 117/B page 68 of the official Moto Morini factory manual aka the Blue book.
Misalignment can occur when changing the belt.
Cheers Mark
fatblokeabroad
Posts: 26
Joined: 11 Apr 2021 14:39
Location: Puglia, Italy

Re: Ignition timing problems

Post by fatblokeabroad »

Hi Mickey,
Even at idle, the ANT1 mark is lagging behind the case mark. I have tried moving the magnetic housing its full travel within the kidney slots and there is no noticeable difference. I have now set it back to the arrow pointing at the punched dot.
I think I will remove the rotor and ensure the woodruff key is in the right way around and check the clearance after that I will try what Mark has suggested and check the cam alignment. I would have thought that a 30 Deg misalignment would have made it impossible to set the valve timing. I check tor TDC using a dial gauge in the plug hole when I do valve clearances. and at PMS1 the piston was TDC and the valve clearance was 0.1mm as required. I will check anyway as I'm still `well baffled'.
MickeyMoto
Posts: 2415
Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Ignition timing problems

Post by MickeyMoto »

What happens if you do the check on the rear cylinder?
fatblokeabroad
Posts: 26
Joined: 11 Apr 2021 14:39
Location: Puglia, Italy

Re: Ignition timing problems

Post by fatblokeabroad »

I'm pretty certain the result was the same only harder to see as I had not white marked ART 2. To be honest I can't be sure as I tried so many permutations. I will try again on Weds, I'm not allowed to tinker tomorrow due to it being wifee's birthday, I did say that, as a treat she could help but it was not a positive or pleasant response. :(
fatblokeabroad
Posts: 26
Joined: 11 Apr 2021 14:39
Location: Puglia, Italy

Re: Ignition timing problems

Post by fatblokeabroad »

Joy of Joys!!
Thanks for all your input, Mark hit the nail on the head and on close inspection the cam gear was one tooth out on the belt. With the alignment fixed I have strobed the timing marks and all is well (on both pots) and I have adjustment via the pick-up housing. I have re-adjusted the carbs and balanced them again but I think a jet modification will be on the cards, but one thing at a time.
Thanks again for all the help and advice, I hope I may have a pearl of wisdom to share on day, but don't hold your collective breaths.
:D
Gary
MickeyMoto
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Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Ignition timing problems

Post by MickeyMoto »

Good news!
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